Coal mine exhaust air waste heat utilization and heating fresh air solution

Overview
Coal mine exhaust air refers to the low-temperature hot air discharged from the mine ventilation system. It contains a certain amount of heat energy and is usually discharged directly, resulting in energy waste. Exhaust air waste heat utilization technology recovers this part of heat energy and uses it for heating fresh air or other purposes, which not only improves energy utilization efficiency, but also reduces energy consumption and environmental pollution. This proposal introduces the principle and technical solution of coal mine exhaust air waste heat recovery and the specific application of heating fresh air.
Principle of Utilization of Waste Heat from Lack of Air
The waste heat recovery of exhaust air is mainly based on heat pump technology or heat exchanger system, which extracts the low-temperature heat energy in the exhaust air and converts it into usable high-temperature heat energy. Its working principle is as follows:
Thermal energy capture: The exhaust air passes through a heat exchanger or heat pump system to transfer heat to the working medium (such as water or refrigerant).
Thermal energy conversion: Heat pumps raise the temperature of thermal energy through a process of compression and expansion, making it suitable for heating or other purposes.
Thermal energy output: The converted high-temperature thermal energy is used to heat fresh air, provide heating or hot water.
Lack of wind waste heat utilization plan
1. Heat pump system
Equipment: air source heat pump or water source heat pump.
Workflow:
The exhaust air passes through the evaporator, releasing heat to the refrigerant.
After the refrigerant is heated by the compressor, it transfers heat to water or air in the condenser.
The heated medium is used for fresh air preheating or heating.
Advantages:
High efficiency and energy saving, COP (energy efficiency ratio) is usually above 3.0.
Suitable for low temperature environment and stable operation.
Application scenarios: Suitable for mines in cold areas in winter, heating fresh air or heating buildings.
2. Heat exchanger system
Equipment: Plate heat exchanger or tube heat exchanger.
Workflow:
The exhaust air and the fresh air exchange heat in the heat exchanger, and the heat of the exhaust air is directly transferred to the fresh air.
Fresh air is preheated before entering the ventilation system, reducing heating energy consumption.
Advantages:
Simple structure and low maintenance cost.
Suitable for scenarios with lower heat demand.
Application scenarios: Suitable for mild climate areas or mines with small fresh air preheating requirements.
3. Composite system
Equipment: Heat pump combined with heat exchanger.
Workflow:
The heat exchanger initially recovers the heat of the exhausted air and preheats the fresh air.
The heat pump further increases the heat temperature to meet higher temperature requirements.
Advantages: It takes into account both high efficiency and economy, and can adapt to various working conditions.
Application scenarios: Suitable for deep mines or comprehensive energy utilization projects with large heat demand.
Heating fresh air solution
Heating fresh air is an important application of waste heat from exhaust air, especially in cold areas, where fresh air needs to be heated to a suitable temperature to ensure the working environment in the mine. The following is a specific plan:
1. Fresh air preheating system
process:
The exhaust air passes through the heat exchanger and transfers heat to the incoming fresh air.
The preheated fresh air enters the heating device (such as electric heating or heat pump) to further reach the target temperature.
Advantages: Reduce energy consumption of heating devices and reduce operating costs.
Case: A coal mine uses a plate heat exchanger, which increases the fresh air preheating temperature by 10-15°C and saves 30% heating energy.
2. Heat pump directly supplies fresh air
process:
The heat from the exhaust air is extracted through a heat pump system to heat circulating water or air.
The heated medium is directly used to heat fresh air and sent into the mine ventilation system.
Advantages: efficient, stable, suitable for large-scale fresh air heating.
Case: A mine uses an air source heat pump, the exhaust air heat recovery rate reaches 60%, and the fresh air temperature is stable at above 20℃.
3. Intelligent control system
Function:
Real-time monitoring of exhaust air temperature, flow rate and fresh air demand.
Automatically adjust the operating status of the heat pump or heat exchanger to optimize energy efficiency.
Advantages: Improve system operation efficiency and reduce manual intervention.
Case: A mine introduced a PLC control system, and the heat utilization rate increased by 15%.
Advantages and economic benefits
Energy saving and emission reduction: Recovering the heat from exhaust air can reduce the use of traditional coal or electric heating and reduce CO2 emissions.
Economical: The initial investment is high, but the operating cost is low and the payback period is generally 3-5 years.
Environmental benefits: Reduce heat emissions and improve the environment around the mining area.
Case analysis: A coal mine wind-deficient waste heat project saves about 2,000 tons of standard coal annually, reduces CO2 emissions by about 5,000 tons, and has an annual economic benefit of one million yuan.
Implementation Notes
Analysis of exhaust air characteristics: Measure the temperature, flow rate and stability of exhaust air to ensure that the system design is reasonable.
Equipment selection: Choose the appropriate heat pump or heat exchanger model based on the mine size and climatic conditions.
Maintenance management: Clean the heat exchanger regularly and check the heat pump system to prevent efficiency loss.
Policy support: Take advantage of the national energy conservation and emission reduction subsidy policy to reduce project investment costs.
in conclusion
Coal mine exhaust air waste heat utilization technology provides a sustainable energy solution for green mining. The heating fresh air solution effectively recovers the exhaust air heat through a heat pump or heat exchanger system, which not only improves the mine working environment, but also significantly reduces energy consumption and emissions. Combined with intelligent control and policy support, this solution has broad application prospects and economic value.